Evaluation od Safety and Performance of the Omega™ LAA (Left Atrial Appendage) Occluder and Omega™ Delivery System in Patients With Non-Valvular Atrial Fibrillation and High Bleeding Risk

Inclusion Criteria:

1. 18 years of age or older
2. Documented paroxysmal, persistent, or permanent non-valvular atrial fibrillation (AF)
3. At increased risk of stroke or systemic embolism defined as CHADS2 score (Risk ofStroke with AF". VA Palo Alto Medical Center and at Stanford University: theSportsmedicine Program and the Cardiomyopathy Clinic:Congestive/Hypertension/Age/Diabetes/Stroke): ≥ 2 or a CHA2DS2-VASc score (Congestive/Hypertension/Age/Diabetes/Stroke/Vascular disease/Sex) ≥ 3
4. Deemed, by investigator, to be unsuitable or contraindicated for long term oralanticoagulation therapy due to high bleeding risk
5. To have suitable anatomy for percutaneous Left Atrial Appendage occlusion procedurewith a single Omega™ device
6. Able and willing to comply with the required medication regimen post-device implant
7. Able to understand and willing to provide written informed consent to participate inthe study
8. Able to and willing to return for required follow-up visits and examinations.

Exclusion Criteria:

1. Requires long-term oral anticoagulation therapy for any indication other than atrialfibrillation
2. Contraindicated for or allergic to aspirin/clopidogrel, warfarin or novel oralanticoagulant (NOAC) use
3. Implanted with a mechanical heart valve prosthesis thus requiring long term oralanticoagulation
4. Has any contraindications for a percutaneous catheterization procedure (e.g. subjectis too small to accommodate the transoesophageal echocardiogram (TEE/TOE) probe orrequired catheters, or subject has active infection or bleeding disorder)
5. Women of childbearing potential who are, or plan to become, pregnant during the timeof the study (method of assessment per physician discretion)
6. Stroke or transient ischemic attack (TIA) within 6 weeks prior to implant procedure
7. Underwent any cardiac or non-cardiac intervention or surgery within 30 days prior toimplant, or intervention or surgery is planned within 60 days after implant procedure
8. Myocardial infarction (MI) within 90 days prior to implant
9. New York Heart Association Class IV Congestive Heart Failure
10. Left ventricular ejection Fraction (LVEF) ≤ 30%
11. Reversible cause of AF (i.e. secondary thyroid disorders, acute alcohol intoxication,trauma, recent major surgical procedures)
12. Left atrial appendage is obliterated or surgically ligated
13. Resting heart rate >110 bpm
14. Thrombocytopenia (defined as < 70,000 platelets/mm3) or anaemia with haemoglobinconcentration of < 10 g/dl (i.e. anaemia as determined by the investigator which wouldrequire transfusion)
15. Actively enrolled or plans to enrol in a concurrent clinical study in which the activetreatment arm may confound the results of this trial
16. Active endocarditis or other infection producing bacteraemia
17. Subject has a known malignancy or other illness where life expectancy is less than 2years
18. Impaired renal function with eGFR (Estimated Glomerular Filtration Rate) <40ml/min/1.73 m2
19. More than mild hepatic failure, i.e. ALT (Alanine Aminotransferase), AST (AspartateAminotransferase), or Alkalic Phosphatase >2× upper limit of normal Echocardiographic Exclusion Criteria:
20. Intracardiac thrombus - including Left Atrial Appendage - visualized byechocardiographic imaging
21. Existing circumferential pericardial effusion >2mm
22. Significant mitral valve stenosis (i.e. mitral valve area <1.5 cm2)
23. High risk patent foramen ovale (PFO), defined as an atrial septal aneurysm (atrialseptal excursion >15mm; excursion defined as maximal protrusion of the ASA (AtrialSeptal Aneurysm) beyond the plane of the atrial septum during cardiac cycle) or largeshunt (substantial passage of bubbles, i.e. ≥ 25, within 3 cardiac cycles fromappearing in the right atrium)
24. Complex atheroma with mobile plaque of the descending aorta and/or aortic arch
25. Cardiac tumour
26. Left Atrial Appendage anatomy cannot accommodate an Omega™ device (as per IFU)
27. Placement of the device would interfere with any intracardiac or intravascularstructure.